Transcript 2.8 ppt

EXAMPLE
Warm-Up1Exercises
Solve a literal equation
Solve ax + b = c for x. Then use the solution to solve
2x + 5 = 11.
SOLUTION
STEP 1 Solve ax + b = c for x.
ax + b = c
ax = c – b
c–b
x=
a
Write original equation.
Subtract b from each side.
Assume a  0. Divide each side by a.
Warm-Up
Exercises
GUIDED
PRACTICE
for Example 1
Solve the literal equation for x. Then use the
solution to solve the specific equation
1. a – bx = c; 12 – 5x = –3
Warm-Up
Exercises
GUIDED
PRACTICE
for Example 1
Solve the literal equation for x. Then use the
solution to solve the specific equation
2. ax = bx + c; 11x = 6x + 20
Warm-Up2Exercises
EXAMPLE
Rewrite an equation
Write 3x + 2y = 8 so that y is a function of x.
3x + 2y = 8
2y = 8 – 3x
y = 4 – 3x
2
Write original equation.
Subtract 3x from each side.
Divide each side by 2.
Warm-Up
Exercises
GUIDED
PRACTICE
3.
Write 5x + 4y = 20 so that y is a function of x.
Warm-Up Exercises
Warm-Up
Exercises
GUIDED
PRACTICE
4.
for Examples 2 and 3
The perimeter P of a rectangle is given by the
formula P = 2l + 2w where l is the length and w is the
width.
a. Solve the formula for the width w.
Warm-Up3Exercises
EXAMPLE
Solve and use a geometric formula
1
The area A of a triangle is given by the formula A = bh
2
where b is the base and h is the height.
a.
Solve the formula for the height h.
b.
Use the rewritten formula to find the
height of the triangle shown, which
has an area of 64.4 square meters.
Warm-Up4Exercises
EXAMPLE
Solve a multi-step problem
Temperature
You are visiting Toronto, Canada, over the weekend.
A website gives the forecast shown. Find the low
temperatures for Saturday and Sunday in degrees
5
Fahrenheit. Use the formula C = (F – 32) where C is
9
the temperature in degrees Celsius and F is the
temperature in degrees Fahrenheit.
Warm-Up4Exercises
EXAMPLE
Solve a multi-step problem
SOLUTION
STEP 1 Rewrite the formula. In the problem, degrees
Celsius are given and degrees Fahrenheit
need to be calculated. The calculations will be
easier if the formula is written so that F is a
function of C.
5
C = 9 (F – 32)
Write original formula.
9 5
9
C = · (F – 32)
5 9
5
9
C = F – 32
5
9
C + 32 = F
5
9
Multiply each side by , the
5
reciprocal of 5 .
9
Simplify.
Add 32 to each side.
Warm-Up Exercises
1.
Write the equation 15 = 5y – 4x so that y is a
function of x.
2.
Solve C = 2pr for r.
3.
Solve V = 1 Bh for B.
3